Terminal apparatus, base station apparatus, and communication method

ABSTRACT

A signal that is transmitted to a terminal apparatus itself is demodulated with high precision, and throughput is improved. A terminal apparatus that communicates with a base station apparatus includes a signal detection unit that demodulates a signal that is transmitted to the terminal apparatus itself, based on first modulation mapping in a case where a predetermined transmission mode is configured, and that demodulates a signal based on second modulation mapping in a case where a transmission mode other than the predetermined transmission mode is configured. A base station apparatus that communicates with a terminal apparatus includes a modulation unit that performs modulation using first modulation mapping from bits addressed to a plurality of terminal apparatuses, in a case where a predetermined transmission mode is configured, and that performs modulation using second modulation mapping from bits that are addressed to one terminal apparatus, in a case where a transmission mode other than the predetermined transmission mode is configured.

TECHNICAL FIELD

The present invention relates to a terminal apparatus, a base stationapparatus, and a communication method.

BACKGROUND ART

In recent years, with the spread of smartphones and tablets, the amountof traffic in mobile transmission has been increasing exponentially, andis expected to increase in the future as well. In NPL 1, Non-OrthogonalMultiple Access (NOMA) in which a terminal remote from and a terminalclose to a base station share the same resource is described as onemeasure to cope with such increase in the amount of wireless traffic. Abase station apparatus that uses the NOMA assigns a high power and alow-rate Modulation and Coding Scheme (MCS) to a remote terminal and alow power and a high-rate MCS to a nearby terminal and adds modulationsignals generated based on this assignment.

CITATION LIST Non Patent Literature

-   NPL 1: RP-142315, “Enhanced Multiuser Transmission and Network    Assisted Interference Cancellation”, 3GPP TSG RAN Meeting #66,    December 2014

SUMMARY OF INVENTION Technical Problem

However, because in the NOMA, a plurality of terminal apparatuses sharethe same resource, it is desired to remove or suppress the interferencesignals and to demodulate with high precision a signal that istransmitted to the terminal apparatus itself.

An object of the present invention, which was made in view of thissituation, is to provide a terminal apparatus, a base station apparatus,and a communication method, in all of which a signal that is transmittedto the terminal apparatus itself can be demodulated with high precisionand an improvement in throughput is possible.

Solution to Problem

In order to deal with the problems described above, constitutions of aterminal apparatus, a base station apparatus, and a communication methodaccording to the present invention are as follows.

(1) That is, a terminal apparatus according to the present invention isa terminal apparatus that communicates with a base station apparatus andincludes a signal detection unit that demodulates a signal that istransmitted to the terminal apparatus itself, based on first modulationmapping in a case where a predetermined transmission mode is configured,and that demodulates a signal that is transmitted to the terminalapparatus itself, based on second modulation mapping in a case where atransmission mode other than the predetermined transmission mode isconfigured.

(2) Furthermore, in the terminal apparatus according to (1) describedabove, the signal detection unit obtains the first modulation mappingbased on the second modulation mapping, and demodulates the signal thatis transmitted to the terminal apparatus itself.

(3) Furthermore, in the terminal apparatus according to (1) describedabove, the signal detection unit demodulates the signal that istransmitted to the terminal apparatus itself, based on the secondmodulation mapping.

(4) Furthermore, the terminal apparatus according to (3) described abovefurther includes a reception unit that receives information indicating amodulation scheme for an interference signal and information relating toa transmit power of the interference signal, from the base stationapparatus, in which the signal detection unit demodulates a signal thatis transmitted to the terminal apparatus itself based on the informationindicating the modulation scheme for the interference signal, theinformation relating to the transmit power of the interference signal,and the second modulation mapping.

(5) That is, a base station apparatus according to the present inventionis a base station apparatus that communicates with a terminal apparatusand includes a modulation unit that performs modulation using firstmodulation mapping from bits addressed to a plurality of terminalapparatuses, in a case where a predetermined transmission mode isconfigured, and that performs modulation using second modulation mappingfrom bits addressed to one terminal apparatus, in a case where atransmission mode other than the predetermined transmission mode isconfigured.

(6) Furthermore, in the base station apparatus according to (5)described above, the first modulation mapping and the second modulationmapping correspond to a gray code.

(7) Furthermore, in the base station apparatus according to (5)described above, the first modulation mapping is determined based on thesecond modulation mapping.

(8) Furthermore, the base station apparatus according to (7) describedabove further includes a transmission unit that transmits informationindicating a modulation scheme for an interference signal andinformation relating to a transmit power of the interference signal, inwhich the first modulation mapping is determined based on theinformation indicating the modulation scheme for the interferencesignal, the information relating to the transmit power of theinterference signal, and the second modulation mapping.

(9) Furthermore, a communication method according to the presentinvention is a communication method for use in a terminal apparatus, themethod including a step of demodulating a signal that is transmitted tothe terminal apparatus itself, based on first modulation mapping in acase where a predetermined transmission mode is configured, anddemodulating a signal that is transmitted to the terminal apparatusitself, based on second modulation mapping in a case where atransmission mode other than the predetermined transmission mode isconfigured.

(10) Furthermore, a communication method according to the presentinvention is a communication method for use in a base station apparatus,the method including a step of performing modulation using firstmodulation mapping from bits addressed to a plurality of terminalapparatuses, in a case where a predetermined transmission mode isconfigured, and performing modulation using second modulation mappingfrom bits addressed to one terminal apparatus, in a case where atransmission mode other than the predetermined transmission mode isconfigured.

Advantageous Effects of Invention

According to the present invention, a terminal apparatus can improvetransmission performance.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of a communication systemaccording to the present embodiment.

FIG. 2 is a schematic block diagram illustrating a configuration of abase station apparatus according to the present embodiment.

FIG. 3 is a diagram illustrating an example of second modulation mappingin compliance with QPSK according to the present embodiment.

FIG. 4 is a diagram illustrating an example of the second modulationmapping in compliance with 16 QAM according to the present embodiment.

FIG. 5 is a diagram illustrating an example of the second modulationmapping in compliance with 64 QAM according to the present embodiment.

FIG. 6 is a diagram illustrating an example of first modulation mappingaccording to the present embodiment.

FIG. 7 is a diagram illustrating an example of the first modulationmapping according to the present embodiment.

FIG. 8 is a schematic block diagram illustrating a configuration of aterminal apparatus according to the present embodiment.

DESCRIPTION OF EMBODIMENTS

A communication system according to the present invention includes abase station apparatus (a transmission apparatus, a cell, a transmissionpoint, a transmit antenna group, a transmit antenna port group, acomponent carrier, or an eNodeB) and a terminal apparatus (a terminal, amobile terminal, a reception point, a reception terminal, a receptionapparatus, a receive antenna group, a receive antenna port group or aUE).

According to the present embodiment, “X/Y” includes the meaning of “X orY”. According to the present embodiment, “X/Y” includes the meaning of“X and Y”. According to the present embodiment, “X/Y” includes themeaning of “X and/or Y”.

FIG. 1 is a diagram illustrating an example of a communication systemaccording to the present embodiment. As illustrated in FIG. 1, thecommunication system according to the present embodiment includes a basestation apparatus 1 and terminal apparatuses 2-1 and 2-2. The terminalapparatuses 2-1 and 2-2 are collectively also referred to as a terminalapparatus 2. Furthermore, coverage 1-1 is a range (a communication area)in which the base station apparatus 1 is capable of making a connect tothe terminal apparatus.

In FIG. 1, in uplink wireless communication from the terminal apparatus2 to the base station apparatus 1, the following uplink physicalchannels are used. The uplink physical channels are used to transmitinformation that is output from a higher layer.

-   -   Physical Uplink Control Channel (PUCCH)    -   Physical Uplink Shared Channel (PUSCH)    -   Physical Random Access Channel (PRACH)

The PUCCH is used to transmit Uplink Control Information (UCI). At thispoint, the Uplink Control Information includes a positiveacknowledgement (ACK) or a negative acknowledgement (NACK) (ACK or NACK)of downlink data (a downlink transport block or a Downlink-SharedChannel (DL-SCH)). The ACK or NACK of the downlink data is also referredto as an HARQ-ACK or HARQ feedback.

Furthermore, the Uplink Control Information includes Channel StateInformation (CSI) for downlink. Furthermore, the Uplink ControlInformation includes a Scheduling Request (SR) that is used to make arequest for a resource for an Uplink-Shared Channel (UL-SCH).

The PUSCH is used to transmit uplink data (an uplink transport block orthe UL-SCH). Furthermore, the PUSCH may be used to transmit the ACK orNACK and/or the Channel State Information, along with the uplink data.Furthermore, the PUSCH may be used to transmit only the Uplink ControlInformation.

Furthermore, the PUSCH is used to transmit an RRC message. The RRCmessage is information or a signal that is processed in a Radio ResourceControl (RRC) layer. Furthermore, the PUSCH is used to transmit a MACControl Element (CE). At this point, the MAC CE is information or asignal that is processed (transmitted) in a Medium Access Control (MAC)layer.

For example, a power headroom may be included in the MAC CE and may bereported through the PUSCH. That is, a MAC CE field may be used toindicate a power headroom level.

The PRACH is used to transmit a random access preamble.

Furthermore, in the uplink wireless communication, an Uplink ReferenceSignal (UL RS) is used as an uplink physical signal. The uplink physicalsignal is not used to transmit the information that is output from thehigher layer, but is used by a physical layer. At this point, aDemodulation Reference Signal (DMRS) and a Sounding Reference Signal(SRS) are included in the Uplink Reference Signal.

The DMRS is associated with transmission of the PUSCH or the PUCCH. Forexample, the base station apparatus 1 uses the DMRS to perform channelreconfiguration of the PUSCH or the PUCCH. The SRS is not associatedwith the transmission of the PUSCH or the PUCCH. For example, the basestation apparatus 1 uses the SRS to measure an uplink channel state.

In FIG. 1, in downlink wireless communication from the base stationapparatus 1 to the terminal apparatus 2, the following downlink physicalchannels are used. The downlink physical channels are used to transmitthe information that is output from the higher layer.

-   -   Physical Broadcast Channel (PBCH)    -   Physical Control Format Indicator Channel (PCFICH)    -   Physical Hybrid automatic repeat request Indicator Channel        (PHICH)    -   Physical Downlink Control Channel (PDCCH)    -   Enhanced Physical Downlink Control Channel (EPDCCH)    -   Physical Downlink Shared Channel (PDSCH)

The PBCH is used to broadcast a Master Information Block (MIB) (aBroadcast Channel (BCH)) that is used in the terminal apparatus 2. ThePCFICH is used to transmit information indicating a region (for example,the number of OFDM symbols) that is used for transmission of the PDCCH.

The PHICH is used to transmit the ACK or NACK of the uplink data that isreceived by the base station apparatus 1. That is, the PHICH is used totransmit an HARQ indicator (HARQ feedback) indicating the ACK or NACK ofthe uplink data.

The PDCCH and the EPDCCH are used to transmit Downlink ControlInformation (DCI). At this point, a plurality of DCI formats are definedfor transmission of the Downlink Control Information. That is, a fieldfor the Downlink Control Information is defined in a DCI format and ismapped to an information bit.

For example, DCI format 1A that is used for scheduling of one PDSCH(transmission of one downlink transport block) in one cell is defined asa DCI format for the downlink.

For example, information relating to PDSCH resource allocation,information relating to a Modulation and Coding Scheme (MCS) for thePDSCH, and the Downlink Control Information such as a TPC command forthe PUCCH are included in the DCI format for the downlink. At thispoint, the DCI format for the downlink is also referred to as a downlinkgrant (or a downlink assignment).

Furthermore, for example, DCI format 0 that is used for scheduling ofone PUSCH (transmission of one uplink transport block) in one cell isdefined as a DCI format for uplink.

For example, information relating to PUSCH resource allocation,information relating to an MCS for the PUSCH, and Uplink ControlInformation such as a TPC command for the PUSCH are included in the DCIformat for the uplink. The DCI format for the uplink is also referred toas an uplink grant (or an uplink assignment).

Furthermore, the DCI format for the uplink can be used to make a request(a CSI request) for the Channel State Information (which is alsoreferred to as received quality information) for the downlink. A RankIndicator (RI) indicating the suitable number of spatial multiplexes, aPrecoding Matrix Indicator (PMI) indicating a suitable precoder, aChannel Quality Indicator (CQI) indicating a suitable transmission rate,and the like correspond to the Channel State Information.

Furthermore, the DCI format for the uplink can be used for aconfiguration indicating an uplink resource to which a channel stateinformation report (CSI feedback report or CSI reporting) that is fedback by the terminal apparatus to the base station apparatus is mapped.For example, the channel state information report can be used for theconfiguration indicating the uplink resource in which Channel StateInformation (Periodic CSI) is regularly (periodically) reported. Thechannel state information report can be used for a mode configuration (aCSI report mode) in which the Channel State Information is regularlyreported.

For example, the channel state information report can be used for theconfiguration indicating the uplink resource in which irregular ChannelState Information (aperiodic CSI) is reported. The channel stateinformation report can be used for the mode configuration (the CSIreporting mode) in which the Channel State Information is irregularlyreported. The base station apparatus 1 can configure any one of theregular channel state information report and the irregular channel stateinformation report. Furthermore, the base station apparatus 1 can alsoconfigure both of the regular channel state information report and theirregular channel state information report.

Furthermore, the DCI format for the uplink can be used for aconfiguration indicating a type of channel state information report thatis fed back by the terminal apparatus to the base station apparatus. Astypes of channel state information reports, there are wideband CSI (forexample, a Wideband CQI), narrowband CSI (for example, a Subband CQI),and the like.

Furthermore, the DCI format for the uplink can be used for a modeconfiguration that includes the regular channel state information reportor the irregular channel state information report and the type ofchannel state information report. For example, there are a mode in whichthe irregular channel state information report and the wideband CSI arereported, a mode in which the irregular channel state information reportand the narrowband CSI are reported, a mode in which the irregularchannel state information report, the wideband CSI, and the narrowbandCSI are reported, a mode in which the regular channel state informationreport and the wideband CSI are reported, a mode in which the regularchannel state information report and the narrowband CSI are reported,and a mode in which the regular channel state information report, thewideband CSI, and the narrowband CSI are reported.

In a case where a PDSCH resource is scheduled using the downlinkassignment, the terminal apparatus 2 receives the downlink data, on thescheduled PDSCH. Furthermore, in a case where a PUSCH resource isscheduled using the uplink grant, the terminal apparatus 2 transmits theuplink data and/or the Uplink Control Information, on the scheduledPUSCH.

The PDSCH is used to transmit the downlink data (the downlink transportblock or the DL-SCH). Furthermore, the PDSCH is used to transmit asystem information block type-1 message. The system information blocktype-1 message is cell-specific (cell-peculiar) information.

Furthermore, the PDSCH is used to transmit a system information message.The system information message includes a system information block Xother than the system information block type-1. The system informationmessage is cell-specific (cell-peculiar) information.

Furthermore, the PDSCH is used to transmit the RRC message. At thispoint, the RRC message that is transmitted from the base stationapparatus 1 may be common to a plurality of terminal apparatuses 2within a cell. Furthermore, the RRC message that is transmitted from thebase station apparatus 1 may be a message (which is also referred to asdedicated signaling) dedicated to a certain terminal apparatus 2. Thatis, UE-specific (UE-peculiar) information is transmitted using a messagededicated to a certain terminal apparatus 2. Furthermore, the PDSCH isused to transmit the MAC CE.

At this point, the RRC message and/or the MAC CE are also referred to ashigher layer signaling.

Furthermore, in the downlink wireless communication, a synchronizationsignal (SS) and a Downlink Reference Signal (DL RS) are used as downlinkphysical signals. The downlink physical signal is not used to transmitthe information that is output from the higher layer, but is used by thephysical layer.

The synchronization signal is used for the terminal apparatus 2 to besynchronized to a frequency domain for and a time domain for thedownlink. Furthermore, the Downlink Reference Signal is used for theterminal apparatus 2 to perform the channel reconfiguration of thedownlink physical channel. For example, the Downlink Reference Signal isused for the terminal apparatus 2 to calculate the Channel StateInformation for the downlink.

At this point, a Cell-specific Reference Signal (CRS), a UE-specificReference Signal (URS) associated with the PDSCH, a DemodulationReference Signal (DMRS) associated with the EPDCCH, a Non-Zero PowerChannel State Information-Reference Signal (NZP CSI-RS), and a ZeroPower Channel State Information-Reference Signal (ZP CSI-RS) areincluded in the Downlink Reference Signal.

The CRS is transmitted in all bands in a subframe, and is used forperforming demodulation of the PBCH/PDCCH/PHICH/PCFICH/PDSCH. The URSassociated with the PDSCH is transmitted in a subframe and a band thatare used for transmission of the PDSCH with which the URS is associated,and is used for performing the demodulation of the PDSCH with which theURS is associated.

The DMRS that is associated with the EPDCCH is transmitted in a subframeand a band that are used for transmission of the EPDCCH with which theDMRS is associated. The DMRS is used to perform demodulation of theEPDCCH with which the DMRS is associated.

A resource for the NZP CSI-RS is configured by the base stationapparatus 1. For example, the terminal apparatus 2 performs signalmeasurement (channel measurement) using the NZP CSI-RS. A resource forthe ZP CSI-RS is configured by the base station apparatus 1. With a zerooutput, the base station apparatus 1 transmits the ZP CSI-RS. Forexample, the terminal apparatus 2 performs interference measurement on aresource to which the NZP CSI-RS corresponds.

At this point, the downlink physical channel and the downlink physicalsignal are also collectively referred to as a downlink signal.Furthermore, the uplink physical channel and the uplink physical signalare also collectively referred to as an uplink signal. Furthermore, thedownlink physical channel and the uplink physical channel are alsocollectively referred to as a physical channel. Furthermore, thedownlink physical signal and the uplink physical signal are alsocollectively referred to as a physical signal.

Furthermore, the BCH, the UL-SCH and the DL-SCH are transport channels.A channel that is used in the MAC layer is referred to as a transportchannel. Furthermore, a unit of a transport channel that is used in theMAC layer is also referred to as a Transport Block (TB) or a MACProtocol Data Unit (PDU). The Transport Block is a unit of data that isdelivered by the MAC layer to the physical layer. In the physical layer,the Transport Block is mapped to a codeword, and coding processing andthe like are performed on every codeword.

FIG. 2 is a schematic block diagram illustrating a constitution of thebase station apparatus according to the present embodiment. Asillustrated in FIG. 2, the base station apparatus is constituted toinclude a higher layer processing unit (a higher layer processing step)101, a control unit (a control step) 102, a transmission unit (atransmission step) 103, a reception unit (a reception step) 104, and atransmit and receive antenna 105. Furthermore, the higher layerprocessing unit 101 is constituted to include a radio resource controlunit (a radio resource control step) 1011 and a scheduling unit (ascheduling step) 1012. Furthermore, the transmission unit 103 isconstituted to include a coding unit (a coding step) 1031, a modulationunit (a modulation step) 1032, a downlink reference signal generatingunit (a downlink reference signal generating step) 1033, a multiplexingunit (a multiplexing step) 1034, and a wireless transmission unit (awireless transmission step) 1035. Furthermore, the reception unit 104 isconstituted to include a wireless reception unit (a wireless receptionstep) 1041, a demultiplexing unit (a demultiplexing step) 1042, ademodulation unit (a demodulation step) 1043, and a decoding unit (adecoding step) 1044.

The higher layer processing unit 101 performs processing of the MediumAccess Control (MAC) layer, a Packet Data Convergence Protocol (PDCP)layer, a Radio Link Control (RLC) layer, and the Radio Resource Control(RRC) layer. Furthermore, the higher layer processing unit 101 generatesinformation necessary to perform control of the transmission unit 103and the reception unit 104, and outputs the generated information to thecontrol unit 102.

The higher layer processing unit 101 receives information relating tothe terminal apparatus, such as a function (UE capability) of theterminal apparatus, from the terminal apparatus. In other words, theterminal apparatus transmits the function of the terminal apparatusitself to the base station apparatus using the higher layer signaling.

It is noted that, as will be described below, information relating tothe terminal apparatus includes information indicating whether or notthe terminal apparatus supports a predetermined function, or informationindicating completion of introduction and test of the predeterminedfunction by the terminal apparatus. It is noted that, as will bedescribed below, whether or not the predetermined function is supportedincludes whether or not the introduction and the test of thepredetermined function is completed. For example, in a case where theterminal apparatus supports the predetermined function, informationindicating that the terminal apparatus supports the predeterminedfunction, or the information indicating the terminal apparatus completesthe introduction and test of the predetermined function is transmitted.For example, in a case where the terminal apparatus does not support thepredetermined function, the information indicating that the terminalapparatus supports the predetermined function, or the informationindicating the terminal apparatus completes the introduction and test ofthe predetermined function is not transmitted. That is, whether or notto transmit the information indicating whether or not the terminalapparatus supports the predetermined function, or the informationindicating that the terminal apparatus completes the instruction andtest of the predetermined function indicates whether or not the terminalapparatus supports the predetermined function.

For example, in the case where the terminal apparatus supports thepredetermined function, the terminal apparatus transmits the information(a parameter) indicating whether or not the predetermined function issupported. In the case where the terminal apparatus does not support thepredetermined function, the terminal apparatus does not transmit theinformation (the parameter) indicating whether or not the predeterminedfunction is supported. That is, whether or not the predeterminedfunction is supported is notified depending on whether or not theinformation (the parameter) indicating whether or not the predeterminedfunction is supported is transmitted. It is noted that the information(the parameter) indicating whether or not the predetermined function issupported may be notified using a bit that is 1, that is, a bit that is0 or a bit that is 1.

Functions of the terminal apparatus include a parameter indicatingwhether or not Non-Orthogonal Multiple Access (NOMA) (Multi-user(MU)-Network assisted Interference suppression and cancellation (NAICS),MU-Interference Cancellation (IC), or superposition coding) issupported. It is noted that the support of the NOMA by the terminalapparatus can be made to be mandatory in a predetermined resource. In acase where the Non-Orthogonal Multiple Access is supported, it can beindicated that information relating to the Non-Orthogonal MultipleAccess, more precisely, Downlink Control Information relating to theNon-Orthogonal Multiple Access and/or configuration formation (assistinformation) in the higher layer, which relates to the Non-OrthogonalMultiple Access, can be received, and/or that PDSCH interference in thesame resource can be removed or suppressed using the same resource usingthe information relating to the Non-Orthogonal Multiple Access.

The base station apparatus 1 can multiplex a plurality of terminalapparatuses without dividing a resource that is a time, a frequency anda space (for example, an antenna port, a beam pattern, and a precodingpattern). A signal that results from the base station apparatus 1multiplexing within the same resource, signals which are transmitted tothe plurality of terminal apparatuses is hereinafter also referred to asa NOMA signal, and transmission of the NOMA signal to destinations, theplurality of terminal apparatuses, by the base station apparatus 1 ishereinafter also referred to NOMA transmission. It is noted that thebase station apparatus 1 can perform the NOMA transmission in such amanner that the plurality of terminals are multiplexed using some or allof resources that are the time, the frequency, and the space.

The radio resource control unit 1011 generates or acquires from a highernode the downlink data (the Transport Block) that is mapped to the PDSCHfor the downlink, the system information, the RRC message, the MAC CE,and the like. The radio resource control unit 1011 outputs the downlinkdata to the transmission unit 103, and outputs other information to thecontrol unit 102. Furthermore, the radio resource control unit 1011manages various pieces of configuration information of the terminalapparatus 2.

The radio resource control unit 1011 can configure information relatingto a transmission mode (TM). Based on information relating to the UEcapability (a UE function) of the terminal apparatus 2, the base stationapparatus 1 can determine the transmission mode. For example, thetransmission mode can include Single Input Single Output (SISO)transmission, Transmit Diversity, Multiple Input Multiple Output (MIMO)transmission, and the like. It is noted that the terminal apparatusnotifies the base station apparatus of the information relating to theUE capability before the configuration of the transmission mode.

The base station apparatus 1 can configure a mode in which the NOMAtransmission is performed. The radio resource control unit 1011 cangenerate information relating to a transmission mode (which ishereinafter also referred to as a “NOMA mode”) that corresponds to theNOMA transmission, for the terminal apparatus 2 that supports the NOMA.Furthermore, the NOMA mode may be notified as information, such as thenumber of times of blind decoding, without being configured as thetransmission mode. The information relating to the NOMA mode, forexample, is transmitted as the higher layer signaling and/or theDownlink Control Information. In a case where the NOMA mode isconfigured, the terminal apparatus 2 removes or suppresses interferencesignal using the information relating to the NOMA mode.

Furthermore, regardless of the transmission mode (more precisely,although in the NOMA mode, and although in a transmission mode otherthan the NOMA mode), the base station apparatus 1 may transmit theinformation relating to the NOMA (assist information, supplementaryinformation, control information, or configuration information) to theterminal apparatus. The information relating to the NOMA is transmittedusing the higher layer signaling and/or a physical layer signal.Information relating to the NOMA includes part or all of informationrelating to a PA, information relating to the transmission mode or atransmit power for the PDSCH of the interference signal, informationrelating to the PMI or the PA of a serving cell, information (orinformation relating to a size such as the number of bits of the DCI)relating to the modulation scheme, the MCS, a redundancy version, aRadio Network Temporary Identifier (RNTI), or the number of times of theblind decoding of DCI, and modulation mapping information. It is notedthat the PA is a transmit power ratio (a power offset) between the PDSCHand the CRS in an OFDM symbol to which the CRS is not mapped. Thetransmission mode is assist information for the terminal apparatus toknow (detect) a transmission mode for the interference signal, such as atransmission mode for the interference signal or a candidate for thetransmission mode in which the serving cell can be configured (is likelyto be configured). Furthermore, modulation mapping will be describedbelow. Furthermore, a modulation scheme indicates a modulation schemefor the terminal apparatus itself and/or a modulation scheme for theinterference signal, and/or a composite modulation scheme. The compositemodulation scheme is a modulation scheme that results from combining themodulation scheme for the terminal apparatus itself and the modulationscheme for the interference signal. For example, in a case where themodulation scheme for the terminal apparatus itself is QPSK and themodulation scheme for the interference signal is QPSK, the compositemodulation scheme is 16 QAM. Furthermore, for example, in a case wherethe modulation scheme for the terminal apparatus itself is 16 QAM andthe modulation scheme for the interference signal is QPSK, the compositemodulation scheme is 64 QAM. It is noted that a modulation symbol whichis generated with the composite modulation scheme is also referred to asa composite modulation symbol.

It is noted that in the example described above, the radio resourcecontrol unit 1011 is described as generating the information relating tothe NOMA mode, but the present embodiment is not limited to this. Forexample, the scheduling unit 1012 can generate the information relatingto the NOMA mode. A method will be described below in which thescheduling unit 1012 generates the information relating to the NOMAmode.

The scheduling unit 1012 can determine frequencies and subframes towhich the physical channels (the PDSCH and PUSCH) are allocated, codingrates of and modulation schemes (or MCSs) and for the physical channels(the PDSCH and the PUSCH), the transmit power, and the like. Thescheduling unit 1012 can perform scheduling, considering the presenceand absence of the terminal apparatus that supports the NOMA. Forexample, in a case where the terminal apparatus 2-2 that approaches thebase station apparatus supports the NOMA, the base station apparatus canperform the scheduling in such a manner that communication with theterminal apparatus 2-1 that is remote from the terminal apparatus 2-2and the base station apparatus is performed using the same resource. Anindex that identifies whether or not the base station apparatus performsthe NOMA can be set to be the CQI, the PMI, the RI, or the like that isfed back from the terminal apparatus, regardless of a distance.Furthermore, only in a case where both of the terminal apparatuses 2-1and 2-2 support the NOMA, the base station apparatus can perform theNOMA on the terminal apparatuses 2-1 and 2-2.

The scheduling unit 1012 can generate the information relating to theNOMA mode. For example, in a case where the terminal apparatuses 2-1 to2-2 are allocated to the same resource, information (for example,resource allocation information) that is used for the scheduling can bethe information relating to the NOMA mode. More precisely, the basestation apparatus 1 can include resource allocation information in theinformation relating to the NOMA, of the terminal apparatus 2.Furthermore, the scheduling unit 1012 can include information other thanthe information that is used for the scheduling, in the informationrelating to the NOMA mode or the information relating to the NOMA. Thescheduling unit 1012 may individually generate the information relatingto the NOMA mode or the information relating to the NOMA, for everyresource block (or which may be a transport block and be a set ofresources other than the transport block), and may individually generatethe information relating to the NOMA mode or the information relating tothe NOMA, for every terminal apparatus 2. More precisely, the basestation apparatus 1 can transmit the information relating to the NOMAfor every resource block, in a state of being included in the DownlinkControl Information. Furthermore, in a case where a plurality ofresources are transmitted to the terminal apparatus 2, the base stationapparatus 1 can include the information relating to the NOMA for onlyone resource block. More precisely, the terminal apparatus 2 receivesthe information relating to the NOMA for every resource block, andremoves or suppresses the interference signal against the resource blockin which the information relating to the NOMA is received.

The scheduling unit 1012 generates information that is used forscheduling of the physical channels (the PDSCH and the PUSCH), based ona result of the scheduling. The scheduling unit 1012 outputs thegenerated information to the control unit 102.

For example, even in a case where the base station apparatus 1 transmitsthe information relating to the NOMA mode, to the terminal apparatus2-2, the base station apparatus 1 and the terminal apparatus 2-2 canperform communication using a transmission method other than the NOMAtransmission. More precisely, in the communication between the basestation apparatus 1 and the terminal apparatus 2-2, the base stationapparatus 1 can use the NOMA transmission for every resource block, anda transmission method other than the NOMA. In this case, the terminalapparatus 2-2 makes a change of a reception procession method for everyresource block that is allocated to a destination that is the terminalapparatus 2-2 itself.

It is noted that, even in a case where the base station apparatus 1allocates the same resource to the terminal apparatuses 2-1 to 2-2, theterminal apparatuses 2-1 to 2-2 can acquire only information relating tothe scheduling for the terminal apparatuses 2-1 to 2-2 itself,respectively. In order for the terminal apparatus 2 to use theinformation relating to the scheduling, as the information relating tothe NOMA mode, among the terminal apparatuses 2, the terminal apparatus(for example, the terminal apparatus 2-2) that supports at least theNOMA preferably acquires information relating to the scheduling for theterminal apparatuses 2-1 to 2-2. The base station apparatus 1 caninclude the information relating to the scheduling for the terminalapparatus 1, in the information relating to the scheduling for theterminal apparatus 2-2. Furthermore, the base station apparatus 1 cantransmit information (for example, a Radio Network Temporary Identifier(RNTI), or the like) necessary to decode the information relating to thescheduling for the terminal apparatuses 2-1 to 2-2, to the terminalapparatus 2.

For example, in a case where the terminal apparatus 2-2 supports theNOMA and where the terminal apparatus 2-1 does not support the NOMA, theradio resource control unit 1011 can generate the information relatingto a NOMA transmission mode or the information relating to the NOMA,only for the terminal apparatus 2-2 that supports the NOMA. Furthermore,the radio resource control unit 1011 can generate information relatingto a transmission mode other than the NOMA mode, for the terminalapparatus 2-1.

In a case where the NOMA mode is configured, and/or in a case where theinformation relating to the NOMA is configured, the base stationapparatus 1 can add signals that are transmitted to the terminalapparatus 2-1 and the terminal apparatus 2-2 using the same resource,and can transmit the resulting signal. The base station apparatus 1 cangenerate each of the signals (the modulation symbols) that aretransmitted to the terminal apparatuses 2-1 and the terminal apparatus2-2, according to the modulation mapping that is a mapping rule for abit and a modulation symbol. In the case where the NOMA mode isconfigured, and/or in the case where the information relating to theNOMA is configured, the terminal apparatus 2 can perform demodulationand/or interference removal, based on the modulation mapping.

Furthermore, the base station apparatus 1 can generate the modulationsymbol using modulation mapping different from that in a case where theNOMA mode is configured and/or the information relating to the NOMA isnot configured, for the terminal apparatus 2 for which the NOMA mode isconfigured and/or for which the information relating to the NOMA isconfigured. Furthermore, in a case where modulation mapping informationis transmitted, or where the modulation mapping information indicatesdifferent modulation mapping, the base station apparatus 1 can generatea modulation symbol using modulation mapping different from that in acase where the modulation mapping information is not transmitted or themodulation mapping information does not indicate different modulationmapping. It is noted that, modulation mapping in the case where the NOMAmode is configured and/or where the information relating to the NOMA isconfigured, or in the case where the modulation mapping information istransmitted and/or where the modulation mapping information indicatesdifferent mapping is also referred to as first modulation mapping.Furthermore, modulation mapping in the case where the NOMA mode is notconfigured and/or where the information relating to the NOMA is notconfigured, or in the case where the modulation mapping information isnot transmitted or where the modulation mapping information does notindicate different mapping is also referred to as second modulationmapping. Furthermore, the modulation symbol that is generated with thefirst modulation mapping is also referred to as a first modulationsymbol and the modulation symbol that is generated with the secondmodulation mapping is also referred to as a second modulation symbol.Furthermore, the first modulation mapping can be set to be modulationmapping that results from combining bits which are addressed to aplurality of terminal apparatuses. Furthermore, the terminal apparatus 2can perform the demodulation based on the first modulation mapping, inthe case where the NOMA mode is configured and/or where the informationrelating to the NOMA is configured, and can perform the demodulationbased on the second modulation mapping, in the case where the NOMA modeis not configured and/or where the information relating to the NOMA isnot configured. Furthermore, the terminal apparatus 2 performs thedemodulation based on the first modulation mapping, in a case where themodulation mapping information is received, or in the case where themodulation mapping information indicates different modulation mapping,and performs the demodulation based on the second modulation mapping, ina case where the modulation mapping information is not received, or inthe case where the modulation mapping information does not indicate themodulation mapping. It is noted that the modulation mapping informationis information relating to the modulation mapping, and for example, isinformation indicating the first modulation mapping, or is informationindicating the second modulation mapping.

Furthermore, the terminal apparatus 2 can determine whether or not theremoval or the suppression of the interference signal is performed usingthe modulation mapping information. For example, in a case where theterminal apparatus 2 receives information indicating the firstmodulation mapping, the removal and the suppression of the interferencesignal can be performed.

It is noted that FIG. 3 illustrates an example of the second modulationmapping in compliance with QPSK, FIG. 4 illustrates an example of thesecond modulation mapping in compliance with or 16 QAM, and FIG. 5illustrates an example of the second modulation mapping in compliancewith 64 QAM.

Furthermore, in the case of a predetermined downlink control informationformat and in the case of a downlink control information format otherthan the predetermined downlink control information format, the basestation apparatus 1 can generate a modulation symbol based on differentmodulation mapping. In the case of a predetermined downlink controlinformation format and in the case of a downlink control informationformat other than the predetermined downlink control information format,the terminal apparatus can perform the demodulation and/or theinterference removal based on different modulation mapping. It is notedthat the predetermined downlink control information format may be a DCIformat dedicated for the NOMA mode, which is associated with the NOMAmode, and may be a DCI format that notifies the information relating tothe NOMA using DCI format 1C or the like.

Furthermore, the base station apparatus 1 can apply a certain rule(formula) to a second modulation symbol, and can generate a firstmodulation symbol. For example, the base station apparatus 1 can obtainthe first modulation mapping based on the second modulation symbol foranother apparatus that performs the NOMA transmission, and can generatethe first modulation symbol. At this time, the terminal apparatus 2 candemodulate the first modulation symbol based on the second modulationsymbol for another apparatus, which is detected.

The higher layer processing unit 101 can generate information fordemodulating the first modulation symbol. In order to demodulate thereceived first modulation symbol, the terminal apparatus 2 preferablyhas part or all of information relating to MCS that is allocated to theterminal apparatuses 2-1 to 2-2, information relating to a method of thefirst modulation mapping that is used by the base station apparatus 1,and information relating to powers (or power ratios) that are allocatedto the terminal apparatuses 2-1 to 2-2. More precisely, the base stationapparatus 1 preferably notifies the terminal apparatus 2 of part or allof the information relating to the MCS that is allocated to the terminalapparatuses 2-1 to 2-2, the information relating to the method of thefirst modulation mapping that is used by the base station apparatus 1,and the information relating to the powers that are allocated to theterminal apparatuses 2-1 to 2-2. Alternatively, the base stationapparatus 1 and the terminal apparatus 2 preferably have part or all ofthe information relating to the MCS that is allocated to the terminalapparatuses 2-1 to 2-2, the information relating to the method of thefirst modulation mapping that is used by the base station apparatus 1,and the information relating to the powers that are allocated to theterminal apparatuses 2-1 to 2-2, which is in common use.

The higher layer processing unit 101 can generate the informationrelating to the modulation mapping. The information relating to themodulation mapping is information indicating the method of themodulation mapping that is used by the base station apparatus 1. Thebase station apparatus 1 can notify the terminal apparatus 2 of theinformation relating to the modulation mapping.

Based on information that is input from the higher layer processing unit101, the control unit 102 generates a control signal for performingcontrol of the transmission unit 103 and the reception unit 104.Furthermore, based on the information that is input from the higherlayer processing unit 101, the control unit 102 determines the MCS.Furthermore, based on the information that is input from the higherlayer processing unit 101, the control unit 102 determines the number ofcodewords. Furthermore, based on the information that is input from thehigher layer processing unit 101, the control unit 102 determines thenumber of layers, an antenna port number, and a scrambling identity (ascrambling identifier).

The control unit 102 generates the Downlink Control Information, basedon the information that is input from the higher layer processing unit101, and outputs the generated Downlink Control Information to thetransmission unit 103. In the case of a primary cell, the base stationapparatus may include the configuration information in the higher layerin a secondary cell, in the Downlink Control Information.

The transmission unit 103 generates the Downlink Reference Signal inaccordance with the control signal that is input from the control unit102, codes and modulates the HARQ indicator, the Downlink ControlInformation, and the downlink data, which are input from the higherlayer processing unit 101, multiplexes the PHICH, the PDCCH, the EPDCCH,the PDSCH, and the Downlink Reference Signal, and transmits theresulting signal to the terminal apparatus 2 through the transmit andreceive antenna unit 105. It is noted that in a case where a secondframe structure is used, the base station apparatus is made to multiplexat least the PDSCH and not to multiplex the Downlink ControlInformation. Furthermore, in the second frame structure, a frequencyinterval or a time interval of the Downlink Reference Signal can beincreased much more than in a first frame structure. Furthermore, thebase station apparatus can transmit control information of a signal thatis allocated to the second frame structure, using the first framestructure.

The coding unit 1031 performs coding on the HARQ indicator, the DownlinkControl Information, and the downlink data, which are input from thehigher layer processing unit 101. When performing the coding, the codingunit 1031 uses a coding scheme that is determined in advance, such asblock coding, convolutional coding, or turbo coding, or uses a codingscheme that is determined by the radio resource control unit 1011.

The modulation unit 1032 performs modulation on coding bits that areinput from the coding unit 1031, using a modulation scheme that isdetermined in advance, such as Binary Phase Shift Keying (BPSK),quadrature Phase Shift Keying (QPSK), 16 quadrature amplitude modulation(QAM), 64 QAM, or 256 QAM, or using a modulation scheme that isdetermined by the radio resource control unit 1011. When it is assumedthat the number of bits that are allocated to a certain resource elementis N and bits are b0, and so forth up to bN−1, the second modulationsymbol s that can be generated in a modulation scheme that has a higherorder than QPSK or QPSK modulation scheme can be generated as expressedin Equations (1) to (3).

$\begin{matrix}\lbrack {{Math}.\mspace{14mu} 1} \rbrack & \; \\{a_{N} = \sqrt{\frac{3}{2( {2^{N} - 1} )}}} & (1) \\{{{Re}\lbrack s\rbrack} = {a_{N}\lbrack {\sum\limits_{q = 0}^{\frac{N}{2} - 1}\; {2^{\frac{N}{2} - 1 - q}( {- 1} )^{q}{\prod\limits_{q^{\prime} = 0}^{q}\; ( {1 - {2\; b_{2q^{\prime}}}} )}}} \rbrack}} & (2) \\{{{Im}\lbrack s\rbrack} = {a_{N}\lbrack {\sum\limits_{q = 0}^{\frac{N}{2} - 1}\; {2^{\frac{N}{2} - 1 - q}( {- 1} )^{q}{\prod\limits_{q^{\prime} = 0}^{q}\; ( {1 - {2\; b_{{2q^{\prime}} + 1}}} )}}} \rbrack}} & (3)\end{matrix}$

However, N is an even number greater than 1. Re[s] and Im[s] are a realpart and an imaginary part of s, respectively. Furthermore, in a casewhere N=1, that is, in the case of BPSK, s=1−b0. FIG. 3 is a diagramillustrating QPSK (N=2) that can be generated with Equations (1) to (3).FIG. 4 is a diagram illustrating 16 QAM (N=4) that can be generated withEquations (1) to (3). FIG. 5 is a diagram illustrating 64 QAM (N=6) thatcan be generated with Equations (1) to (3).

An example of the first modulation symbol that is generated by themodulation unit 1032 is described. As will be described below, the firstmodulation symbol may be a modulation symbol that includes bits whichare addressed to both of the terminal apparatuses 2-1 to 2-2, which aregenerated using the first modulation mapping and the second modulationmapping, or may be a modulation symbol that includes bits which areaddressed to any one of the terminal apparatuses 2-1 to 2-2, which aregenerated using the first modulation mapping and the second modulationmapping. An example will be described below in which the firstmodulation symbol that includes composite bits is generated. It isassumed that the number of bits that are addressed to the terminalapparatus 2-1 is N1 and that the number of bits that are addressed tothe terminal apparatus 2-2 is N2. It is assumed that b0, and so forth upto bN1−1 are bits that are addressed to the terminal apparatus 2-1 andthat bN1 and so forth up to bN1+N2−1 are bits that are addressed to theterminal apparatus 2-2. A combination of bits that are addressed to allterminal apparatuses 2, in one resource element that is multiplexed withthe NOMA, is also referred to as the composite bits. More precisely, inthe case where the NOMA mode is configured and/or where the informationrelating to the NOMA is configured, or in a case where the modulationmapping information indicates the first modulation mapping, the basestation apparatus 1 can combine bits that are addressed to the terminalapparatus 2-1 and the terminal apparatus 2-2 and thus can generate amodulation symbol. In other words, the base station apparatus 1 cantransmit a composite modulation symbol that results from combiningsymbols for the terminal apparatus 2-1 and the terminal apparatus 2-2,to the terminal apparatus 2-2, and can transmit a modulation symbol forthe terminal apparatus 2-1, to the terminal apparatus 2-1. In the casewhere the NOMA mode is configured and/or where the information relatingto the NOMA is configured, or in a case where the modulation mappinginformation indicates the first modulation mapping, the terminalapparatus 2-2 can determine that some of the composite bits are bitswhich are addressed to the terminal apparatus 2-2 itself and theremaining bits are bits that are addressed to another apparatus, and canperform the demodulation.

For example, the first modulation symbol s can be generated withEquations (4) to (5) that follow.

$\begin{matrix}\lbrack {{Math}.\mspace{14mu} 2} \rbrack & \; \\{{{Re}\lbrack s\rbrack} = {{\sqrt{p_{1}}{a_{N_{1}}\lbrack {\sum\limits_{q = 0}^{\frac{N_{1}}{2} - 1}\; {2^{\frac{N_{1}}{2} - 1 - q}( {- 1} )^{q}{\prod\limits_{q^{\prime} = 0}^{q}\; ( {1 - {2\; b_{2q^{\prime}}}} )}}} \rbrack}} + {\sqrt{p_{2}}{a_{N_{2}}\lbrack {\sum\limits_{q = \frac{N_{1}}{2}}^{\frac{N_{1} + N_{2}}{2} - 1}\; {2^{\frac{N_{1} + N_{2}}{2} - 1 - q}( {- 1} )^{q}{\prod\limits_{q^{\prime} = 0}^{q}\; ( {1 - {2\; b_{2q^{\prime}}}} )}}} \rbrack}}}} & (4) \\{{{Im}\lbrack s\rbrack} = {{\sqrt{p_{1}}{a_{N_{1}}\lbrack {\sum\limits_{q = 0}^{\frac{N_{1}}{2} - 1}\; {2^{\frac{N_{1}}{2} - 1 - q}( {- 1} )^{q}{\prod\limits_{q^{\prime} = 0}^{q}\; ( {1 - {2\; b_{{2q^{\prime}} + 1}}} )}}} \rbrack}} + {\sqrt{p_{2}}{a_{N_{2}}\lbrack {\sum\limits_{q = \frac{N_{1}}{2}}^{\frac{N_{1} + N_{2}}{2} - 1}\; {2^{\frac{N_{1} + N_{2}}{2} - 1 - q}( {- 1} )^{q}{\prod\limits_{q^{\prime} = 0}^{q}\; ( {1 - {2\; b_{{2q^{\prime}} + 1}}} )}}} \rbrack}}}} & (5)\end{matrix}$

However, each of p1 and p2 indicates a power that is assigned to each ofthe terminal apparatus 2-1 and the terminal apparatus 2-2, a powerratio, or a power offset. It is assumed here that p1+p2=1. Thisgeneration can make possible the modulation mapping with bits as awhole, as is the case with a gray code, and the transmission performancecan be improved. Furthermore, because the terminal apparatus 2-1 is aterminal apparatus that is remote from the base station apparatus, agreat value is set for p1 and thus the transmission performance in theterminal apparatus 2-1 can be improved. FIG. 6 illustrates an example ofthe first modulation mapping that is generated using Equations (4) and(5), and is a diagram in a case where QPSK and 16 QAM are allocated tothe terminal apparatus 2-1 and the terminal apparatus 2-2, respectively.Initial 2 bits are addressed to the terminal apparatus 2-1 and theremaining 4 bits are addressed to the terminal apparatus 2-2. Becausethe gray code results in which a certain modulation point and amodulation point in the vicinity of the certain modulation point is onlyat a one-bit distance away from each other, the transmission performancecan be improved. Furthermore, because a comparison between FIGS. 5 and 6shows that FIGS. 5 and 6 are the same in allocation of bits, if themodulation mapping is known, the demodulation can be performed withalmost the same processing as in the case of the second modulationmapping. It is noted that the order in which bits are allocated to eachterminal apparatus 2 is not limited. For example, the first bit and thefourth bits are addressed to the terminal apparatus 2-1 and the other 4bits are addressed to the terminal apparatus 2-2, and other orders canalso be set to be used.

It is noted that FIG. 7 is a diagram illustrating another example of thefirst modulation mapping. In FIGS. 6 and 7, different types of mappingare performed, but both also result in the gray code. For example,initial 2 bits that result from the first modulation mapping that isillustrated in FIGS. 6 and 7 indicate allocation of a QPSK modulationsymbol to the terminal apparatus 2-1, but are different from each otherin terms of an allocation position of the modulation symbol. In thismanner, the first modulation mapping according to the present inventionmay be possible as long as it satisfies the attribute of the gray code,and a plurality of types of first modulation mapping are present.

A method in which the modulation unit 1032 generates the firstmodulation symbol for the NOMA transmission is not limited to themethods that are based on Equations (4) and (5). Another method in whichthe modulation unit 1032 generates the first modulation symbol for theNOMA transmission will be described below.

As an example, a case will be described below where, in the case of theNOMA transmission, the base station apparatus 1 allocates QPSK to theterminal apparatus 2-1 and allocates 16 QAM to the terminal apparatus2-2. First, it is assumed that the modulation unit 1032 performsmultiplexing on each of the QPSK modulation points that are transmittedto the terminal apparatus 2-1, which are illustrated in FIG. 3, and on16 QAM modulation points for the terminal apparatus 2-2, which areillustrated in FIG. 4, and generates a modulation symbol 1032 a. Themodulation symbol 1032 a that is generated by the modulation unit 1032has the same constitution as the modulation symbol that is illustratedin FIG. 5.

When it comes to the modulation symbol 1032 a, bit allocation to theneighboring modulation symbol point does not satisfy a requirement forthe gray code (All Humming distances at the neighboring modulationsymbol point are not 1). The modulation unit 1032 performs differentoperations on four quadrants of the modulation symbol 1032 a, and thuscan generate a modulation symbol that satisfies the requirement for thegray code. For example, the modulation unit 1032 performs point symmetrymoving on the first quadrant (for example, the upper right quadrant),with the middle of 16 modulation points in the first quadrant as areference, and thus can obtain a modulation symbol constitution in whichthe modulation point (001111) is the closest to the middle. In the samemanner, the modulation unit 1032 performs the point symmetry moving,with the middle of 16 modulation point in each of the quadrants as areference, and thus generates a modulation symbol 1032 b. In anothermethod, for the terminal apparatus 2-2, the base station apparatus 1 cangenerate the first modulation symbol that is based on the modulationscheme (more precisely, the second modulation mapping) for the terminalapparatus 2-1. First, among modulation symbol points for the terminalapparatus 2-1, one modulation symbol point is set to be a referencesymbol point. At this point, because QPSK is used for the terminalapparatus 2-1, for example, the reference symbol point is set to be(00). The reference symbol point and the modulation symbol that istransmitted to the terminal apparatus 2-1 are exclusive-ORed for everybit. For example, in a case where the modulation point that istransmitted to the terminal apparatus 2-1 is (10), the result of theexclusive-ORing for every bit is (10). It is noted that the referencesymbol point is set to (00) in the case of QPSK, the modulation symbolpoint that is transmitted is exclusive-ORed, it is not desirable toperform exclusive-ORing calculation. If bits at the second modulationsymbol point that corresponds to bits that are a result 1 of theexclusive-ORing are inverted, the result is a first modulation symbolpoint. For example, the result of the exclusive-ORing is set to be (10).In an example in FIG. 4, in 16 QAM, because the first and second bitscorrespond to QPSK, the first bit in 16 QAM is inverted with the result(10) of the exclusive-ORing. A combination of a QPSK symbol point and a16 QAM symbol point that results from the bit inversion results in acomposite modulation symbol point. When these operations are performedwith all symbol points, the result is as illustrated in FIG. 7, themodulation symbol 1032 b can satisfy the requirement for the gray code.

The base station apparatus 1 can transmit a signal indicating that theNOMA is performed on the terminal apparatus 2-2 and/or that theinterference removal or suppression is needed. The base stationapparatus 1 can notify the terminal apparatus 2-2 of both of p1 and p2,any one of p1 and p2, or a ratio (an offset) between p1 and p2. Theterminal apparatus 2-2 receives the signal indicating that the NOMA isperformed and/or that the interference removal or suppression is needed,from the base station apparatus 1, and can suitably demodulate bits thatare addressed to the terminal apparatus 2-2 itself, based on the signal.

A downlink reference signal generating unit 1033 generates as theDownlink Reference Signal a sequence that is already known to theterminal apparatus 2, which is obtained according to a rule that isdetermined in advance based on a physical cell identity (PCI) or thelike for identifying the base station apparatus 1. Furthermore, thedownlink reference signal generating unit 1033 can generate theUE-specific Reference Signal based on the scrambling identity. Thedownlink reference signal generating unit 1033 can generate differentUE-specific Reference Signals that are used for the terminal apparatus2-1 and the terminal apparatus 2-2. At that time, the UE-specificreference signal to the terminal apparatus 2-1 can be multiplied by asquare root of p1. Accordingly, although the terminal apparatus 2-1 doesnot know p1, the terminal apparatus 2-1 can demodulate the bits that areaddressed to the terminal apparatus 2-1 itself. Furthermore, theUE-specific reference signal to the terminal apparatus 2-2 can bemultiplied by a square root of p2. Accordingly, the terminal apparatus2-2 can measure a power of the UE-specific Reference Signal. Theterminal apparatus 2-2, when detecting a lower power than normal, candetermine that the NOMA transmission is performed. In such a case, theterminal apparatus 2-2 can demodulate bits that are addressed to theterminal apparatus 2-2 itself based on the modulation symbol that isgenerated with Equations (4) to (5).

It is noted that the base station apparatus 1 may set any one of p1 andp2 to 0, and may transmit information to that effect to the terminalapparatus 2, and thus may instantly provide a notice that the NOMA isnot performed. In a case where p1 is set to 0, the base stationapparatus 1 can generate a modulation symbol based on the secondmodulation mapping. In this case, even in a case where the NOMA mode isconfigured and/or even in case where the information relating to theNOMA is configured, the terminal apparatus 2, if the terminal apparatus2 receives a notice that an interference power is 0 or detects that theinterference power is 0, the terminal apparatus 2 does not perform theremove or suppression of the interference signal. Furthermore, even in acase where the terminal apparatus 2-2 receives the informationindicating the first modulation mapping, if the terminal apparatus 2-2receives the notice that the interference power is 0 or detects that theinterference power is 0, the terminal apparatus 2-2 can perform thedemodulation based on the second modulation mapping.

In a case where the downlink reference signal generating unit 1033transmits the same UE-specific Reference Signal that is used for theterminal apparatuses 2-1 and 2-2 that perform the NOMA, the base stationapparatus 1 can notify the terminal apparatus 2-1 of both of p1 and p2or any one of p1 and p2. Accordingly, the terminal apparatus 2-1 cansuitably demodulate bits that are addressed to the terminal apparatus2-1 itself.

A multiplexing unit 1034 multiplexes a modulation symbol of eachchannel, which results from the modulation, and the Downlink ReferenceSignal and the Downlink Control Information, which are generated. Moreprecisely, the multiplexing unit 1034 maps the modulation symbol of eachchannel, which results from the modulation, and the Downlink ReferenceSignal and the Downlink Control Information, which are generated, toresource elements.

The wireless transmission unit 1035 performs Inverse Fast FourierTransform (IFFT) on a modulation symbol and the like that result fromthe multiplexing, performs modulation in compliance with an OFDM scheme,attaches a Cyclic Prefix (CP) to the OFDM symbol that results from theOFDM modulation, and generates a digital signal in a baseband. Thewireless transmission unit 1035 converts the generated digital signal inthe baseband into an analog signal in a desired band, using filtering,Digital-to-Analog (DA) conversion, frequency conversion, poweramplification, and the like. The wireless transmission unit 1035 outputsthe generated analog signal to a transmit and receive antenna 105 fortransmission.

In accordance with the control signal that is input from the controlunit 102, the reception unit 104 outputs information, which results fromdemultiplexing, demodulating, and decoding a reception signal that isreceived from the terminal apparatus 2 through the transmit and receiveantenna 105, to the higher layer processing unit 101.

A wireless reception unit 1041 converts an uplink signal that isreceived from the transmit and receive antenna 105 into a digital signalin the baseband, using the frequency conversion, the filtering, theAnalog-to-Digital (AD) conversion, amplitude control, and the like.

The wireless reception unit 1041 removes a portion that is equivalent tothe CP from the digital signal that results from the conversion. Thewireless reception unit 1041 performs Fast Fourier Transform (FFT) onthe signal from which the CP is removed, extracts a signal in thefrequency domain, and outputs the extracted signal to the demultiplexingunit 1042.

The demultiplexing unit 1042 demultiplexes the signal that is input fromthe wireless reception unit 1041 into the PUCCH, the PUSCH, and thesignal such as the Uplink Reference Signal. It is noted that, thedemultiplexing is performed based on radio resource allocationinformation that is determined in advance by the base station apparatus1, using the radio resource control unit 1011, and that is included inthe uplink grant that is notified to each of the terminal apparatuses 2.

Furthermore, the demultiplexing unit 1042 performs channel compensationon the PUCCH and the PUSCH. Furthermore, the demultiplexing unit 1042demultiplexes the Uplink Reference Signal.

A demodulation unit 1043 performs Inverse Discrete Fourier Transform(IDFT) on the PUSCH, acquires the modulation symbol, and performsreception signal demodulation on each of the modulation symbols on thePUCCH and the PUSCH, using the modulation scheme that is determined inadvance, such as BPSK, QPSK, 16 QAM, 64 QAM, or 256 QAM, or using themodulation scheme that is notified, in advance, with the uplink grant,to each terminal apparatus 2 by the base station apparatus 1 itself. Itis noted that the Inverse Discrete Fourier Transform may be the InverseFast Fourier Transform in accordance with the number of subcarriers onthe PUSCH.

A decoding unit 1044 performs the decoding on coding bits of the PUCCHand the PUSCH that result from the demodulation, at a coding rate incompliance with the coding scheme that is determined in advance, whichis determined in advance, or at a coding rate which is notified inadvance with the uplink grant to the terminal apparatus 2 by the basestation apparatus itself, and outputs the uplink data and the UplinkControl Information that result from the decoding, to the higher layerprocessing unit 101. In the case of retransmission of the PUSCH, thedecoding unit 1044 performs the decoding using the coding bits that areinput from the higher layer processing unit 101 and that are retained inan HARQ buffer, and the coding bits that result from the demodulation.

FIG. 8 is a schematic block diagram illustrating a constitution of theterminal apparatus according to the present embodiment. As illustratedin FIG. 8, the terminal apparatus is constituted to include a higherlayer processing unit (a higher layer processing step) 201, a controlunit (a control step) 202, a transmission unit (a transmission step)203, a reception unit (a reception step) 204, a channel stateinformation generating unit (a channel state information generatingstep) 205, and a transmit and receive antenna 206. Furthermore, thehigher layer processing unit 201 is constituted to include a radioresource control unit (a radio resource control step) 2011 and ascheduling information analysis unit (a scheduling information analysisstep) 2012. Furthermore, the transmission unit 203 is constituted toinclude a coding unit (a coding step) 2031, a modulation unit (amodulation step) 2032, an uplink reference signal generating unit (anuplink reference signal generating step) 2033, a multiplexing unit (amultiplexing step) 2034, and a wireless transmission unit (a wirelesstransmission step) 2035. Furthermore, the reception unit 204 isconstituted to include a wireless reception unit (a wireless receptionstep) 2041, a demultiplexing unit (a demultiplexing step) 2042, and asignal detection unit (a signal detection step) 2043.

The higher layer processing unit 201 outputs the uplink data (theTransport Block) that is generated by a user operation and the like, tothe transmission unit 203. Furthermore, the higher layer processing unit201 performs the processing of the Medium Access Control (MAC) layer,the Packet Data Convergence Protocol (PDCP) layer, the Radio LinkControl (RLC) layer, and the Radio Resource Control (RRC) layer.

The higher layer processing unit 201 outputs information indicating thefunction of the terminal apparatus, which is supported by the terminalapparatus itself, to the transmission unit 203.

The higher layer processing unit 201 can refer to the informationrelating to the NOMA mode, and the terminal apparatus 2 can cause theNOMA to be configured or can cause a mode other than the NOMA to beconfigured.

The higher layer processing unit 201 has a function of determining whichmodulation mapping the terminal apparatus 2 uses to perform thedemodulation. For example, the terminal apparatus 2 for which the NOMAis configured refers to the information relating to the MCS that isallocated to the terminal apparatuses 2-1 to 2-2. In a case where theMCS of the terminal apparatus 2 is at a high level, the terminalapparatus 2 can be configured in such a manner that the demodulation isperformed based on the first modulation mapping. In a case where the MCSof the terminal apparatus 2 is at a low level, the terminal apparatus 2can be configured in such a manner that the demodulation is performedbased on the second modulation mapping.

Furthermore, in another method, the terminal apparatus 2 for which theNOMA is configured refers to the information relating to the power thatis allocated to the terminal apparatuses 2-1 to 2-2. In a case where thepower of the terminal apparatus 2 is high, the terminal apparatus 2 canbe configured in such a manner that the demodulation is performed basedon the first modulation mapping. In a case where the power of theterminal apparatus 2 is low, the terminal apparatus 2 can be configuredin such a manner that the demodulation is performed based on the secondmodulation mapping.

Furthermore, in another method, the terminal apparatus 2 for which theNOMA is configured refers to information relating to a mapping method.In a case where the base station apparatus 1 uses the first modulationmapping, the terminal apparatus 2 can be configured in such a mannerthat the modulation is performed based on the first modulation mapping.In a case where the base station apparatus 1 uses the second modulationmapping, the terminal apparatus 2 can be configured in a such a mannerthat the modulation is performed based on the second modulation mapping.

Furthermore, in another method, the terminal apparatus 2 for which theNOMA is configured can be configured in such a manner that thedemodulation is performed based on the first modulation mapping.

Furthermore, in another method, the terminal apparatus 2 for which theNOMA is configured acquires values of p1 and p2 that are informationrelating to the power that is allocated to the terminal apparatus 2itself and to the power that is allocated to the terminal apparatusesthat are NOMA-multiplexed. In a case where the power that is allocatedto the terminal apparatus itself is low, the terminal apparatus 2 can beconfigured in such a manner that the demodulation is performed using thefirst modulation mapping. In a case where the power that is allocated tothe terminal apparatus 2 itself is high, the terminal apparatus can beconfigured in such a manner that the demodulation is performed using thesecond modulation mapping.

Furthermore, in another method, the terminal apparatus 2 for which theNOMA is configured can be configured in such a manner that thedemodulation is performed using the first modulation mapping, in a casewhere the terminal apparatus 2 is configured by the base stationapparatus 1 to decode the DCI format for the NOMA (or in a case wherethe terminal apparatus 2 is configured to demodulate the DCI that hasbits of which the number corresponds to the DCI format for the NOMA),and can be configured in such a manner that the demodulation isperformed using the second modulation mapping, in a case where theterminal apparatus 2 is configured by the base station apparatus 1 todecode a DCI format other than the DCI format dedicated to the NOMA.

Furthermore, in another method, the terminal apparatus 2 for which theNOMA is configured can be configured in such a manner that thedemodulation is performed using the first modulation mapping due to theDCI or the second modulation mapping.

The radio resource control unit 2011 manages various pieces ofconfiguration information of the terminal apparatus itself. Furthermore,the radio resource control unit 2011 generates information that ismapped to each channel in the uplink and outputs the generatedinformation to the transmission unit 203.

Furthermore, the radio resource control unit 2011 can acquire theinformation relating to the NOMA mode, which is obtained from the basestation apparatus 1, and can output the acquired information to adetermination unit 2013.

The scheduling information analysis unit 2012 interprets the DownlinkControl Information that is received through the reception unit 204 anddetermines scheduling information. The scheduling information analysisunit 2012 can determine whether or not the NOMA is performed with aresource element for the terminal apparatus itself. Furthermore, thescheduling information analysis unit 2012 generates the controlinformation in order to perform the control of the reception unit 204and the transmission unit 203 based on the scheduling information, andoutputs the generated control information to the control unit 202.

Based on the information that is input from the higher layer processingunit 201, the control unit 202 generates a control signal for performingthe control of the reception unit 204 and the transmission unit 203. Thecontrol unit 202 outputs the generated control signal to the receptionunit 204 and the transmission unit 203 and performs the control of thereception unit 204 and the transmission unit 203. The control unit 202outputs the Uplink Control Information that includes terminalinformation and the like, and the uplink data, to the transmission unit203. At this point, the terminal information includes informationindicating whether or not the terminal apparatus has a function ofdemodulating a NOMA signal.

Furthermore, the scheduling information analysis unit 2012 can acquirethe information relating to the NOMA mode, which is transmitted by thebase station apparatus 1, and can output the acquired information to thedetermination unit 2013.

In a case where in a radio resource to which the terminal apparatus 2itself is allocated, other terminal apparatuses are allocated in anoverlapping manner, the scheduling information analysis unit 2012 candetermine that the base station apparatus 1 performs the NOMAtransmission of the radio resource, and can output informationindicating that the NOMA transmission is performed, as the informationrelating to the NOMA mode, to the determination unit 2013.

The determination unit 2013 acquires the information relating to theNOMA mode, which is output by the radio resource control unit 2011 orthe scheduling interpretation unit 2012. Based on the acquiredinformation relating to the NOMA mode, the determination unit 2013determines whether or not the base station apparatus 1 transmits thePDSCH using the NOMA transmission (information that results from thedetermination is hereinafter also referred to as NOMA determinationinformation). The determination unit 2013 can output the NOMAdetermination information to the reception unit 204.

For example, the terminal apparatus 2 can determine whether or not thePDSCH is demodulated as the NOMA signal using the NOMA determinationinformation. In addition, for example, the NOMA determinationinformation can also be one-bit information indicating whether or notthe base station apparatus 1 performs the NOMA transmission. The NOMAdetermination information, for example, may be configured for every setof resources. Additionally, the DCI in the NOMA mode is notified by thebase station apparatus to the terminal apparatus, but in a case wherethe DCI is detected in a UE-specific search space, the determinationunit can determine that the NOMA signal is transmitted, and can performsignal detection on the PDSCH that is designated by the DCI.

Furthermore, processing in which the terminal apparatus 2 thatdemodulates the PDSCH as the NOMA signal includes removing (canceling orsuppressing) a signal (which is hereinafter also referred to as theinterference signal) that is transmitted to another terminal apparatus.Methods in which the terminal apparatus 2 removes the interferencesignal, for example, include Symbol Level Interference Cancellation(SLIC) that performs the interference removal according to a result ofthe demodulation of the interference signal, Code word LevelInterference Cancellation (CWIC) that performs the interference removalaccording to a result of the decoding of the interference signal,Maximum Likelihood Detection (MLD) that searches for the most similarone among transmission signal candidates, and the like.

The control unit 202 controls the transmission unit 203 in such a mannerthat the CSI which is generated by the channel state informationgenerating unit 205 is transmitted to the base station apparatus.

In accordance with the control signal that is input from the controlunit 202, the reception unit 204 outputs information, which results fromdemultiplexing, demodulating, and decoding a reception signal that isreceived from the base station apparatus through the transmit andreceive antenna 206, to the higher layer processing unit 201.

The wireless reception unit 2041 converts a downlink signal that isreceived through the transmit and receive antenna 206 into a digitalsignal in the baseband, using the frequency conversion, the filtering,the AD conversion, the amplitude control, and the like.

Furthermore, the wireless reception unit 2041 removes a portion that isequivalent to the CP from the digital signal that results from theconversion, performs the Fast Fourier Transform on the signal from whichthe CP is removed, and extracts a signal in the frequency domain.

The demultiplexing unit 2042 demultiplexes a signal that results fromthe extraction, into the PHICH, the PDCCH, the EPDCCH, the PDSCH, and/orthe Downlink Reference Signal. Furthermore, the demultiplexing unit 2042performs channel compensation on the PHICH, the PDCCH, and the EPDCCHbased on a channel estimate of a desired signal that is acquired fromchannel measurement, detects the Downlink Control Information, andoutputs the detected Downlink Control Information to the control unit202. It is noted that in a case where the reception signal is a signalthat is transmitted using the second frame structure, if the DownlinkControl Information is not transmitted in the second frame structure,the demultiplexing unit 2042 does not perform detection of the DownlinkControl Information. Furthermore, the control unit 202 outputs the PDSCHand a channel estimate of the desired signal to the signal detectionunit 2043. It is noted that channel estimation is performed based on thenumber of layers for the terminal apparatus itself, the antenna portnumber, and the scrambling identity, which are input from the controlunit 202.

The signal detection unit 2043 detects the downlink data (the TransportBlock), using the PDSCH and the channel estimate, and outputs a resultof the detection to the higher layer processing unit 201.

A case where the terminal apparatus 2-1 demodulates the NOMA signal isdescribed. In a case where both of powers p1 and p2, or any one ofpowers p1 and p2 is notified, the signal detection can be performedbased on p1. In a case where the UE-specific reference signal (or theCRS) is multiplied by a square root of p1 without powers p1 and p2 beingnotified, the signal detection performs using the channel estimate thatis calculated using the UE-specific reference signal (or the CRS), andthus bits that are addressed to the terminal apparatus 2-1 itself can bedemodulated.

A case where the terminal apparatus 2-2 demodulates the NOMA signal isdescribed. In the case where both of powers p1 and p2, or any one ofpowers p1 and p2 is notified, the signal detection can be performedbased on p1 and p2. On this occasion, with Equations (4) and (5), it canbe determined that the modulation symbol is generated. Alternatively, ina case where the modulation symbol as illustrated in FIG. 7 is employed,the signal detection can be performed based on this. In a case where theUE-specific reference signal is multiplied by a square root of p2without powers p1 and p2 being notified, the power of the UE-specificreference signal is measured, and thus it can be determined whether ornot the NOMA is performed. Furthermore, the terminal apparatus 2-2 cancalculate p1 and p2. Based on p1 and p2, the terminal apparatus 2-2 candemodulate bits that are addressed to the terminal apparatus 2-2 itself.It is noted that NOMA demodulation by the terminal apparatus 2-2, forexample, can first detect bits that are addressed to the terminalapparatus 2-1 itself, can subtract a reception signal replica that canbe generated from the bits that are addressed to the terminal apparatus2-1, from the reception signal that uses resource elements involved, andcan demodulate bits that are addressed to the terminal apparatus 2-2itself, from the reception signal that results from performing thesubtraction.

It is noted that processing by the signal detection unit 2043 in a casewhere both of powers p1 and p2 are not notified is described. In thiscase, the processing by the signal detection unit 2043 varies accordingto the NOMA determination information. Based on the NOMA determinationinformation, the signal detection unit 2043 can determine whether or notthe demodulation of the NOMA signal is to be performed.

A case in which the signal processing unit 2043 determines that thedemodulation of the NOMA signal is not to be performed (for example, theterminal apparatus 2-1) is described. The signal processing unit 2043calculates the channel estimate using the reference signal (for example,the URS, the CRS, the CSI-RS, or the like) in the terminal apparatus2-1, which is transmitted by the base station apparatus 1. Using thecalculated channel estimate, the signal processing unit 2043 can performchannel compensation of the Transport Block that is allocated to theterminal apparatus, and can demodulate the information.

A case in which the signal detection unit 2043 determines that the NOMAsignal is to be demodulated (for example, the terminal apparatus 2-2) isdescribed. The NOMA signal that is transmitted by the base stationapparatus 1 includes the interference signal (the PDSCH for the terminalapparatus 2-1). In a case where it is determined that the demodulationof the NOMA signal is to be performed, the signal detection unit 2043performs the demodulation of the NOMA signal, recognizing that the basestation apparatus 1, for example, uses a method (the modulation mapping)of labeling the modulation symbol that is illustrated in FIG. 7. In themethod (the modulation mapping) of labeling the modulation symbol thatis illustrated in FIGS. 6 and 7, because neighboring symbols arenecessarily different only by one bit in size from each other in a bitsequence, the gray code can be maintained with bits as a whole, leadingto an improvement in the transmission performance.

The transmission unit 203 generates the Uplink Reference Signal inaccordance with the control signal, which is input from the control unit202, performs the coding and the modulation on the uplink data (theTransport Block), which is input from the higher layer processing unit201, multiplexes the PUCCH, the PUSCH, and the generated UplinkReference Signal, and transmits a result of the multiplexing to the basestation apparatus through the transmit and receive antenna 206.

The coding unit 2031 performs the coding, such as the convolutionalcoding or the block coding, on the Uplink Control Information that isinput from the higher layer processing unit 201. Furthermore, the codingunit 2031 performs the turbo coding, based on information that is usedfor scheduling of the PUSCH.

The modulation unit 2032 performs the modulation on coding bits, whichare input from the coding unit 2031, in compliance with a modulationscheme that is notified with the Downlink Control Information, such asBPSK, QPSK, 16 QAM, or 64 QAM, or in compliance with a modulation schemethat is determined in advance for every channel.

The uplink reference signal generating unit 2033 generates a sequencethat is obtained according to a rule (formula) which is determined inadvance, based on the physical cell identity (PCI) (also referred to asa Cell ID or the like) for identifying the base station apparatus 1, abandwidth to which the Uplink Reference Signal is mapped, a cyclic shiftthat is notified with the uplink grant, a parameter value for generationof a DMRS sequence, and the like.

In accordance with the control signal that is input from the controlunit 202, the multiplexing unit 2034 re-maps the modulation symbols onthe PUSCH in parallel and then performs Discrete Fourier Transform (DFT)on the re-mapped modulation symbols. Furthermore, the multiplexing unit2034 multiplexes PUCCH and PUSCH signals and the generated UplinkReference Signal for every transmit antenna port. More precisely, themultiplexing unit 2034 maps the PUCCH and PUSCH signals and thegenerated Uplink Reference Signal to resource elements for everytransmit antenna port. It is noted that the Discrete Fourier Transformmay be the Fast Fourier Transform in accordance with the number ofsubcarriers on the PUCCH or the PUSCH.

The wireless transmission unit 2035 performs the Inverse Fast FourierTransform on the signal that results from the multiplexing, performsmodulation in compliance with an SC-FDMA scheme, generates an SC-FDMAsymbol, attaches a CP to the generated SC-FDMA symbol, and generates adigital signal in a baseband. The wireless transmission unit 2035converts the generated digital signal in the baseband into an analogsignal in a desired band, using the filtering, the DA conversion, thefrequency conversion, the power amplification, and the like. Thewireless transmission unit 2035 outputs the generated analog signal tothe transmit and receive antenna 206 for transmission.

By performing the processing as described above, the transmissionperformance can be improved and throughput can be improved.

It is noted that a program running on the base station apparatus and theterminal apparatus according to the present invention is a program (aprogram for causing a computer to perform functions) that controls a CPUand the like in such a manner as to realize the functions according tothe embodiments of the present invention, which are described above.Then, information that is handled in these apparatuses are temporarilyaccumulated in a RAM while being processed. Thereafter, the informationis stored in various ROMs or HDDs, and if need arises, is read by theCPU to be modified or written. Of a semiconductor medium (for example, aROM, a nonvolatile memory card, or the like), an optical storage medium(for example, a DVD, a MO, a MD, a CD, a BD, or the like), a magneticrecording medium (for example, a magnetic tape, a flexible disk, or thelike), and the like, any one may be possible as a recording medium onwhich to store the program. Furthermore, in some cases, the functionsaccording to the embodiments, which are described above, are realized byexecuting the loaded program, and in addition, the functions accordingto the present invention are realized by performing processing inconjunction with an operating system, other application programs, or thelike, based on an instruction from the program.

Furthermore, in a case where the programs are distributed on the market,the programs, each of which is stored on a portable recording medium,can be distributed, or can be transferred to a server computer that isconnected through a network such as the Internet. In this case, astorage device of the server computer also falls within the scope of thepresent invention. Furthermore, some or all of the portions of each ofthe terminal apparatus and the base station apparatus according to theembodiments, which are described above, may be realized as an LSI thatis a typical integrated circuit. Each functional block of a receptionapparatus may be individually built into a chip, and one or several of,or all of the functional blocks may be integrated into a chip. In a casewhere each of the functional blocks is integrated into a circuit, anintegrated circuit control unit is added that controls the functionalblocks.

Furthermore, a technique for the integrated circuit is not limited tothe LSI, and an integrated circuit for the functional block may berealized as a dedicated circuit or a general-purpose processor.Furthermore, if, with advances in semiconductor technology, a circuitintegration technology for a circuit with which an LSI is replaced willappear, it is also possible that an integrated circuit to which such atechnology applies is used.

It is noted that the invention in the present application is not limitedto the embodiments described above. Furthermore, application of theterminal apparatus according to the invention in the present applicationis not limited to a mobile station apparatus. It goes without sayingthat the terminal apparatus can be applied to a stationary-typeelectronic apparatus that is installed indoors or outdoors, or anon-movable-type electronic apparatus, for example, an AV apparatus, akitchen apparatus, a cleaning or washing machine, an air conditioner,office equipment, a vending machine, and other household apparatuses.

The embodiments of the present embodiment are described in detail abovewith reference to the drawings, but specific configurations are notlimited to the embodiments. A design and the like within the scope notdeparting from the gist of the present invention also fall within thescope of the claims.

INDUSTRIAL APPLICABILITY

The present invention is suitable for using a terminal apparatus, a basestation apparatus, and a communication method.

It is noted that, the present international application claims thebenefits of Japanese Patent Application No. 2015-036035 filed on Feb.26, 2015, and the entire contents of Japanese Patent Application No.2015-036035 are incorporated herein by reference.

REFERENCE SIGNS LIST

-   -   1, 1-1, 2-1 BASE STATION APPARATUS    -   2, 2-1, 2-2 TERMINAL APPARATUS    -   1-1 COVERAGE    -   101 HIGHER LAYER PROCESSING UNIT    -   102 CONTROL UNIT    -   103 TRANSMISSION UNIT    -   104 RECEPTION UNIT    -   105 TRANSMIT AND RECEIVE ANTENNA    -   1011 RADIO RESOURCE CONTROL UNIT    -   1012 SCHEDULING UNIT    -   1031 CODING UNIT    -   1032 MODULATION UNIT    -   1033 DOWNLINK REFERENCE SIGNAL GENERATING UNIT    -   1034 MULTIPLEXING UNIT    -   1035 WIRELESS TRANSMISSION UNIT    -   1041 WIRELESS RECEPTION UNIT    -   1042 DEMULTIPLEXING UNIT    -   1043 DEMODULATION UNIT    -   1044 DECODING UNIT    -   201 HIGHER LAYER PROCESSING UNIT    -   202 CONTROL UNIT    -   203 TRANSMISSION UNIT    -   204 RECEPTION UNIT    -   205 CHANNEL STATE INFORMATION GENERATING UNIT    -   206 TRANSMIT AND RECEIVE ANTENNA    -   2011 RADIO RESOURCE CONTROL UNIT    -   2012 SCHEDULING INFORMATION ANALYSIS UNIT    -   2013 DETERMINATION UNIT    -   2031 CODING UNIT    -   2032 MODULATION UNIT    -   2033 UPLINK REFERENCE SIGNAL GENERATING UNIT    -   2034 MULTIPLEXING UNIT    -   2035 WIRELESS TRANSMISSION UNIT    -   2041 WIRELESS RECEPTION UNIT    -   2042 DEMULTIPLEXING UNIT    -   2043 SIGNAL DETECTION UNIT

1-11. (canceled)
 12. A base station apparatus that communicates with aterminal apparatus, the base station apparatus comprising: atransmission unit that transmits downlink data using DCI includinginformation of PDSCH resource allocation and the PDSCH; and a modulationunit that modulates coding bits of the downlink data using modulationmapping to generate a modulation symbol, wherein the modulation mappingincludes first modulation mapping and second modulation mapping, in acase where multi-user superposition coding is configured, whether themodulation mapping is the first modulation mapping or the secondmodulation mapping is given based on at least whether or not the DCI isa predetermined DCI format, and the first modulation mapping is givenbased on a first modulation symbol given by a predetermined sequence.13. The base station apparatus according to claim 12, wherein the firstmodulation symbol is given based on a second modulation symbol givenbased on the second modulation mapping or bit inversion in a real partand/or an imaginary part of the second modulation symbol, according tothe predetermined sequence.
 14. The base station apparatus according toclaim 12, wherein the number of bits of the predetermined sequence is 2.15. The base station apparatus according to claim 12, wherein the firstmodulation mapping is given based on scaling of the second modulationmapping.
 16. The base station apparatus according to claim 12, whereinthe first modulation mapping is given by shifting a signal point from asignal point of the second modulation mapping.
 17. The base stationapparatus according to claim 12, wherein the predetermined sequence is asequence independent of the coding bits.
 18. The base station apparatusaccording to claim 12, wherein the first modulation symbol is given bymodulating the predetermined sequence using third modulation mapping.19. A terminal apparatus that communicates with a base stationapparatus, the terminal apparatus comprising: a reception unit thatreceives downlink data using DCI including information of PDSCH resourceallocation and the PDSCH; and a modulation unit that demodulates amodulation symbol using modulation mapping with respect to coding bitsof the downlink data, wherein the modulation mapping includes firstmodulation mapping and second modulation mapping, in a case wheremulti-user superposition coding is configured, whether the modulationmapping is the first modulation mapping or the second modulation mappingis given based on at least whether or not the DCI is a predetermined DCIformat, and the first modulation mapping is given based on a firstmodulation symbol given by a predetermined sequence.
 20. The terminalapparatus according to claim 19, wherein the first modulation symbol isgiven based on a second modulation symbol given based on the secondmodulation mapping or bit inversion in a real part and/or an imaginarypart of the second modulation symbol, according to the predeterminedsequence.
 21. The terminal apparatus according to claim 19, wherein thenumber of bits of the predetermined sequence is
 2. 22. The terminalapparatus according to claim 19, wherein the first modulation mapping isgiven based on scaling of the second modulation mapping.
 23. The basestation apparatus according to claim 19, wherein the first modulationmapping is given by shifting a signal point from a signal point of thesecond modulation mapping.
 24. The terminal apparatus according to claim19, wherein the predetermined sequence is a sequence independent of thecoding bits.
 25. The terminal apparatus according to claim 19, whereinthe first modulation symbol is given by modulating the predeterminedsequence using third modulation mapping.
 26. A communication method foruse in a base station apparatus, the method comprising: a step oftransmitting downlink data using DCI including information of PDSCHresource allocation and the PDSCH; and a step of modulating coding bitsof the downlink data using modulation mapping to generate a modulationsymbol, wherein the modulation mapping includes first modulation mappingand second modulation mapping, in a case where multi-user superpositioncoding is configured, whether the modulation mapping is the firstmodulation mapping or the second modulation mapping is given based on atleast whether or not the DCI is a predetermined DCI format, and thefirst modulation mapping is given based a first modulation symbol givenby a predetermined sequence.